Devices which provoke the collapse of snow cornices are known in the art, consisting of a gas gun attached to the side of a mountain with its base solidly anchored in a seating consisting of a concrete block and its mouth opening above the snow cover, such as described in U.S. Pat. No. 5,107,765. These guns are designed to provoke avalanches in exposed areas, for example, above ski stations or inhabited areas. The devices are very effective in provoking avalanches in zones known as avalanche corridors, that is, areas consisting primarily of steeply sloped gorges where snow accumulates rapidly and may attain unstable critical masses. They have proven particularly effective on light snow that is not dense and has a high volume of air trapped inside the snow crystals. The movement triggered by detonation provokes a wave effect with strong initial compression, followed by a slower movement that breaks up the snow cover and raises the mass of snow enough to provoke an avalanche. However, in areas where a thick crust is forming rapidly, the action of the explosion above the stabilized, dense snow layer and the shock wave propagated in the air are not sufficient to break the snow cover and trigger an avalanche.
Furthermore, these devices need to be anchored rigidly and very solidly to a mountain side, specifically, by means of a concrete seating anchored to rock. It may be difficult to position such a base on a steep area, or where there is limited access or crumbling rock. This is the often the case along cornices where snow may accumulate on an outcropping and where the rocky base is not always suitable for supporting a reinforced concrete seating for an avalanche-provoking gun as defined above. Moreover, cornices may be quite long and the crest, which defines the extent of snow movement in avalanches, may stretch for dozens or even hundreds of meters. In this case it would be necessary to install several guns in order to effectively provoke an avalanche, thereby compounding the difficulties already enumerated.